Jury still out on water reuse

Image: Free Digital Photos

Over 170 delegates visited the reclamation plant at Goreangab and were guided by staff of the operator, Wingoc, to first hand witness how the city practices direct potable reuse from sewage effluent, a unique practice that was widely hailed in conference papers as one the important future methods of sustainable water management.

During his closing remarks on Wednesday, conference chair Piet du Pisani, however, reminded delegates that the jury on direct potable reuse is still out and in order to get them back in, stigmas associated with reusing water have to be removed by water experts at the conference.

"If water people themselves cannot have a common approach and understanding on the necessity of reuse, it will remain one of the largest stumbling blocks in implementing the practice," noted Du Pisani.

It is therefore important, according to Du Pisani, to treat and provide water of appropriate quality for appropriate use.

"While potable water is at the very high end of the scale and might still be a bridge too far for many countries, treating water to be reused for irrigation, industry, cooling and many other purposes will already lead to great efficiency improvements," he said.

Du Pisani revealed that of the approximately 100,000 chemical compounds developed annually, only roughly 2,000 are tested for their effects on the water environment.

Du Pisani said that "leaves 98,000 potential enemies that enter unnoticed into our effluents. These figures cause panic in certain circles and reuse of effluent is considered too risky by some and many end users will not accept it currently."

However, Du Pisani countered that these same compounds will at any rate end up in many of our 'blue resources', such as rivers, dams and aquifers, which are then utilised without fear and sometimes without proper treatment.

In the mind of people the waste water is too risky to reclaim, but once it is discharged to a natural water body, this risk "disappears", he said, adding: "The folly of this argument should be clear to everyone.".

Quoting from the Rhapsody website Du Pisanni stated: "By 2015, 80 percent of South Africa's fresh water supply will be so badly polluted that no process of purification available in the country will be able to make it fit for human consumption.

If we do not find a completely new source of water all together in about two years, most of Gauteng will be without safe healthy drinking water." He cautioned that the scientific truth of this statement had not been tested, but compromised water sources might very soon be all that is at the disposal of communities across the world.

Du Pisanni noted that it therefore is important to assure end users that reused water, if appropriately treated, can be made absolutely safe.

"The conference focused a lot on micro pollutants and emerging contaminants, as well as on membrane technology and it looks like we are moving in the right direction in assuring end users that reuse is a viable option, although it is important that strong governance and legal frameworks are in place.

The latter is still lacking in many countries. Especially in the developing world, the same water deemed unsuitable for reuse in one community, becomes a resource downstream," he noted.

Du Pisani concluded that one of the hot topics at the conference was public participation and human perception. "I agree fully that without our customers being involved no project will fly. It is however critically important that the end user has access to the correct information and base his approval or disapproval on facts and not on what lobby groups puts in the public arena," he said.